You push a ball to star it rolling along a "perfectly frictionless" surface. how far will the ball roll

Technically, it should roll forever.

Kinetic energy = 1/2mv^2. since the mass is constant we can form a ratio of it's kinetic energy at 60 divided by that at 30 to see ke(60)/ke(30) = +(60^2)/30^2). this may be said to 300% increase.